An examination of the hypothesis that muscarinic, nicotinic and AChE receptor areas each accommodates different conformations of acetylcholine. Enantiomeric specificities for gamma- and beta- substituted acetyl and carbamyl cholines will be demonstrated by tissue and enzyme receptors. Differences in the conformation of the acetyl group will be shown to be a contributing factor to nicotinic and muscarinic activity by examination of enantiomers of muscarine, muscarone and their derivatives and some substituted 3-trimethyl ammonium phenols and their derivatives. Use of ORD-CD, PMR measurements and a thermodynamic study will augment the enzymologic and pharmacologic studies.